Former Manchester United and England midfielder Paul Scholes believes the rivalry developing between City and his club could hinder the national side.
The 36-year-old retired at the end of last season after 466 appearances for the Red Devils and says there was an atmosphere of suspicion between players from rival clubs on international duty.
"There is a big rivalry between clubs in this country and it isn't healthy when you go away on international duty," he told the Sunday Mirror.
"When I was with England, there was always a lot of United players and Liverpool players in the squad and it was plainly obvious that some of our lads didn't like some of their boys and some of their lads didn't like some of us.
"As Mancs and Scousers we were always a bit suspicious of each other and you can't have that kind of thing if you want to be successful at international level."
Scholes is now a coach at United after spending 17 years at Old Trafford.
